External network properties

The default External network is a dynamic network that includes all IP addresses not explicitly included in any other network. The network definition changes dynamically when other networks are defined and modified. It cannot be directly modified or deleted. The External network generally represents the Internet. By default, it has a NAT relationship with all other networks.

Following installation, the External network includes all addresses not defined in the Internal network, the IP address of the Local Host network (127.0.0.1), and the IP address of all other network adapters on the Microsoft Forefront Threat Management Gateway server.